Add exception for missing system requirements

.github/workflows/pull_request.yml

@@ -24,6 +24,18 @@ jobs:
         with:
           python-version: ${{ matrix.python-version }}
 
+      - name: Install Linux System Dependencies
+        if: runner.os=='Linux'
+        run: sudo apt install graphviz
+
+      - name: Install MacOS System Dependencies
+        if: runner.os=='macOS'
+        run: brew install graphviz
+
+      - name: Install Windows System Dependencies
+        if: runner.os=='Windows'
+        run: choco install graphviz
+
       - name: Install poetry
         run: |
           python -m pip install --upgrade pip
@@ -47,4 +59,4 @@ jobs:
       - name: Upload coverage
         # only do it for python 3.6, we don't need to do it for every version
         if: ${{ matrix.python-version == '3.8' && matrix.os == 'ubuntu-latest' }}
-        uses: codecov/codecov-action@v2
+        uses: codecov/codecov-action@v2

src/zenml/integrations/graphviz/__init__.py

@@ -20,6 +20,6 @@ class GraphvizIntegration(Integration):
 
     NAME = GRAPHVIZ
     REQUIREMENTS = ["graphviz>=0.17"]
-
+    SYSTEM_REQUIREMENTS = {"graphviz":"dot"}
 
 GraphvizIntegration.check_installation()

src/zenml/integrations/integration.py

@@ -14,9 +14,11 @@
 from typing import Any, Dict, List, Tuple, Type, cast
 
 import pkg_resources
+import shutil
 
 from zenml.integrations.registry import integration_registry
 from zenml.logger import get_logger
+from zenml.exceptions import DoesNotExistException
 
 logger = get_logger(__name__)
 
@@ -42,10 +44,20 @@ class Integration(metaclass=IntegrationMeta):
 
     REQUIREMENTS: List[str] = []
 
+    SYSTEM_REQUIREMENTS: Dict[str, str] = {}
+
     @classmethod
     def check_installation(cls) -> bool:
         """Method to check whether the required packages are installed"""
         try:
+            for req, command in cls.SYSTEM_REQUIREMENTS.items():
+                result = shutil.which(command)
+
+                if result is None:
+                    raise DoesNotExistException(
+                        f"Unable to find the required packages for {req} on your system. Please install the packages on your system and try again."
+                    )
+
             for r in cls.REQUIREMENTS:
                 pkg_resources.get_distribution(r)
             logger.debug(